# 类和实例


class Student(object):
    def __init__(self, name, score):
        self.name = name
        self.score = score

    def print_info(self):
        print('%s : %s' % (self.name, self.score))

    def get_grade(self):
        if self.score >= 90:
            return 'A'
        if self.score >= 60:
            return 'B'
        else:
            return 'C'


zs = Student('zhangsan', 77)
print(zs.name)
print(zs.score)
zs.print_info()
print(zs.get_grade())
stu = Student('', 0)
print(stu)
print(Student)